[Bf-committers] Fix for crash when selecting an invalid font

[Emil Brink]

Hi,

I've created a small, trivial patch here:
<https://projects.blender.org/tracker/index.php?func=detail&aid=4054&group_id=9&atid=127>
that I believe fixes a crash that happened when selecting a non-existant
International font.

The easiest way to reproduce it is in the patch description in the tracker, but the
short version is:

* Open the Language & Font panel
* Click International Fonts, then Select Font
* Click LOAD UI FONT, without clicking on any font

This crashes Blender for me, every time. The patch seems to help, at least
for me. Comments welcome, of course.

Regards,

/Emil